1. Field of the Invention
Aspects of the present invention relate to a hierarchical mesoporous carbon, a method of manufacturing the same, and a fuel cell using the same. More particularly, aspects of the present invention relate to a hierarchical mesoporous carbon with macropores and dual mesoporosity, which provides a significantly advantageous structure for diffusion of fuel and release of by-products, a method of manufacturing the same, and a support catalyst with improved activity by using the hierarchical mesoporous carbon as a support, and a fuel cell including an electrode using the same.
2. Description of the Related Art
A fuel cell is an electricity-producing system that produces direct current (DC) electricity from an electrochemical reaction of methanol, water, and oxygen. A typical fuel cell has a structure that includes a proton exchange membrane between an anode and a cathode to which a reagent liquid or a reagent gas is supplied.
In the anode, a catalyst separates protons and electrons from hydrogen or methanol. The protons permeate through the proton conducting membrane and the electrons travel through an external circuit. At the cathode, the protons and electrons react with oxygen in the presence of a cathode catalyst to produce electricity. Thus, the catalysts in such a fuel cell structure have an important role.
In a polymer electrolyte fuel cell, an amorphous carbon support on which Pt particles are dispersed is used as a catalyst for the cathode and the anode. In a direct methanol fuel cell, PtRu is used as the anode and Pt is used as the cathode, either as metal particles themselves, or dispersed within amorphous carbon supports.
Since the main source of the manufacturing cost in a fuel cell is the catalyst, it is desirable to reduce the amount of catalyst in order to achieve a competitive fuel cell price. To this end, active research is underway to reduce the catalyst content used in an anode or a cathode by using a carbon support that can increase catalyst activity or distribution compared to a conventional amorphous carbon support.
As a carbon support, ordered mesoporous carbon (OMC), which is effective as a catalyst support, has been suggested due to its large specific surface area and regularly arranged pores (Korean Patent Laid-Open Publication 2001-0001127). Moreover, a newly structured carbon support with macropores and mesopores has also been introduced (Korean Registration No. 0574022), which is manufactured using a method of preparing a template using silica colloid particles, then wrapping a carbon precursor with the template, thereby forming macropores.
Conventional OMC is useful as a support for a catalyst due to its large specific surface area and regularly arranged pores, but the is much room for improvement in terms of providing better fuel supply and by-product transport characteristics.